Based on the quality and packaging, they are tossed out. It would cost far more to collect them, ship them to a cleaning facility, sterilize them, re-fold them into the nice loops, seal them and them ship them back to the airport. I am sure they cost $0.0000001 per unit (yes, exaggeration) out of Asia somewhere.
OT: Wonder if the NRT outbound flights mule them back to the US.